Mapping Pharmacy Deserts in North Carolina: A Geospatial Analysis and Its Implications for University of North Carolina Health's Catchment Population.

BACKGROUND: Pharmacy deserts represent areas where residents face significant challenges to accessing pharmacies. North Carolina (NC) presents an intriguing case study due to its diverse geographic landscape yet lacks extensive research regarding its pharmacy deserts. OBJECTIVES: This study aims to map pharmacy deserts in NC using pharmacy location and Social Determinants of Health (SDOH) data measured using the Social Vulnerability Index (SVI) and descriptively characterize healthcare utilization statistics for University of North Carolina (UNC) Health's catchment population. METHODS: Pharmacy location data was compiled from the NC Board of Pharmacy. Pharmacy deserts were defined based on SVI >0.75 and distance thresholds aligned to United States Department of Agriculture (USDA) standards. Residential characteristics were retrieved from PolicyMap and Social Explorer databases. UNC Health patient utilization data were collected by UNC Pharmacy Data Analytics group for three NC counties. RESULTS: 2,002 NC pharmacies met inclusion criteria. 17.2% urban tracts (1.3M residents) and 4.25% rural tracts (0.14M residents) were identified as pharmacy deserts (adj. p<0.001). Those residing in deserts had significantly less internet access, annual medical cost per capita, and access to homeless relief services as well as significantly higher food insecurity rates and Medicare cost per capita (adj. p <0.001). UNC specific healthcare utilization statistics for the three assessed counties were all poorer in deserts compared to non-deserts within the same counties (p>0.05). CONCLUSION: A geospatial map with the location of pharmacy deserts in NC was created to highlight differences in patient healthcare utilization, affecting rural and urban areas. By incorporating SDOH predictors, this study provides a more nuanced map of NC pharmacy deserts compared to reviewing distance to pharmacies alone. Higher rates of emergency room and inpatient visits in counties with more residents in pharmacy deserts suggests potential health outcomes associated with limited pharmacy access.

Rural representation of the surveillance, epidemiology, and end results database.

PURPOSE: SEER data are widely used to study rural-urban disparities in cancer. However, no studies have directly assessed how well the rural areas covered by SEER represent the broader rural United States. METHODS: Public data sources were used to calculate county level measures of sociodemographics, health behaviors, health access and all cause cancer incidence. Driving time from each census tract to nearest Commission on Cancer certified facility was calculated and analyzed in rural SEER and non-SEER areas. RESULTS: Rural SEER and non-SEER counties were similar with respect to the distribution of age, race, sex, poverty, health behaviors, provider density, and cancer screening. Overall cancer incidence was similar in rural SEER vs non-SEER counties. However, incidence for White, Hispanic, and Asian patients was higher in rural SEER vs non-SEER counties. Unadjusted median travel time was 53 min (IQR 34-82) in rural SEER tracts and 54 min (IQR 35-82) in rural non-SEER census tracts. Linear modeling showed shorter travel times across all levels of rurality in SEER vs non-SEER census tracts when controlling for region (Large Rural: 13.4 min shorter in SEER areas 95% CI 9.1;17.6; Small Rural: 16.3 min shorter 95% CI 9.1;23.6; Isolated Rural: 15.7 min shorter 95% CI 9.9;21.6). CONCLUSIONS: The rural population covered by SEER data is comparable to the rural population in non-SEER areas. However, patients in rural SEER regions have shorter travel times to care than rural patients in non-SEER regions. This needs to be considered when using SEER-Medicare to study access to cancer care.

Availability of Hospital Resources and Specialty Services for Stroke Care in North Carolina.

OBJECTIVES: Effective regionalization of acute stroke care requires assessment and coordination of limited hospital resources. We described the availability of stroke-specific hospital resources (neurology specialty physicians and neuro-intensive care unit [neuro-ICU] bed capacity) for North Carolina overall and by region and population density. We also assessed daily trends in hospital bed availability. METHODS: This statewide descriptive study was conducted with data from the State Medical Asset Resource Tracking Tool (SMARTT), a Web-based system used by North Carolina to track available medical resources within the state. The SMARTT system was queried for stroke-specific physician and bed resources at each North Carolina hospital during a 1-year period (June 2015-May 2016), including daily availability of neuro-ICU beds. We compared hospital resources by geographic region and population density (metropolitan, urban, and rural). RESULTS: Data from 108 acute care hospitals located in 75 of 100 counties in North Carolina were included in the analysis. Fifty-seven percent of hospitals had no neurology specialty physicians. Western and eastern North Carolina had the lowest prevalence of these physicians. Most hospitals (88%) had general ICUs, whereas only 17 hospitals (16%) had neuro-ICUs. Neuro-ICUs were concentrated in metropolitan areas and in central North Carolina. On average, there were 276 general ICU and 27 neuro-ICU beds available statewide each day. Daily neuro-ICU bed availability was lowest in eastern and southeastern regions and during the week compared with weekends. CONCLUSIONS: In North Carolina, stroke-specific hospital subspecialists and resources are not distributed evenly across the state. Daily bed availability, particularly in neuro-ICUs, is lacking in rural areas and noncentral regions and appears to decrease on weekdays. Regionalization of stroke care needs to consider the geographic distribution and daily variability of hospital resources.

Climate Shocks and Migration: An Agent-Based Modeling Approach.

This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative and quantitative analyses of a well-studied demographic field site, Nang Rong district, Northeast Thailand. With this model, we simulate patterns of migration under four weather regimes in a rice economy: 1) a reference, 'normal' scenario; 2) seven years of unusually wet weather; 3) seven years of unusually dry weather; and 4) seven years of extremely variable weather. Results show relatively small impacts on migration. Experiments with the model show that existing high migration rates and strong selection factors, which are unaffected by climate change, are likely responsible for the weak migration response.

Changing crops in response to climate: virtual Nang Rong, Thailand in an agent based simulation.

The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely economic outcomes, but included elements of bounded rationality in dependence on household demography. The socioeconomic dynamics are endogenous in the system, and climate changes were added as exogenous drivers. Villages changed their agricultural effort in many different ways. Most villages reduced the amount of land under cultivation, primarily with reduction in jasmine rice, but others did not. The variation in responses to climate change indicates potential sensitivity to initial conditions and path dependence for this type of system. The differences between our virtual villages and the real villages of the region indicate effects of bounded rationality and limits on model applications.

Patient Characteristics Associated With Phone and Video Visits at a Tele-Urgent Care Center During the Initial COVID-19 Response: Cross-Sectional Study.

BACKGROUND: Health systems rapidly adopted telemedicine as an alternative health care delivery modality in response to the COVID-19 pandemic. Demographic factors, such as age and gender, may play a role in patients' choice of a phone or video visit. However, it is unknown whether there are differences in utilization between phone and video visits. OBJECTIVE: This study aimed to investigate patients' characteristics, patient utilization, and service characteristics of a tele-urgent care clinic during the initial response to the pandemic. METHODS: We conducted a cross-sectional study of urgent care patients using a statewide, on-demand telemedicine clinic with board-certified physicians during the initial phases of the pandemic. The study data were collected from March 3, 2020, through May 3, 2020. RESULTS: Of 1803 telemedicine visits, 1278 (70.9%) patients were women, 730 (40.5%) were aged 18 to 34 years, and 1423 (78.9%) were uninsured. There were significant differences between telemedicine modalities and gender (P<.001), age (P<.001), insurance status (P<.001), prescriptions given (P<.001), and wait times (P<.001). Phone visits provided significantly more access to rural areas than video visits (P<.001). CONCLUSIONS: Our findings suggest that offering patients a combination of phone and video options provided additional flexibility for various patient subgroups, particularly patients living in rural regions with limited internet bandwidth. Differences in utilization were significant based on patient gender, age, and insurance status. We also found differences in prescription administration between phone and video visits that require additional investigation.

Bacterial pathogens isolated from raw meat and poultry compared with pathogens isolated from children in the same area of rural Thailand.

To better understand the epidemiology of bacterial food borne pathogens in children, in relation to pathogens in meats from a market in rural Thailand, we collected 73 cultures samples from raw chicken, pork and fish at a local market where diarrheal disease surveillance was conducted. Standard methods were employed to isolate, identify and serotype enteric pathogens from children and food samples. Antibiotic susceptibility testing was performed. Ninety-seven percent of food samples were contaminated with at least one enteric pathogen. The pathogens most commonly isolated from food were Salmonella spp (84%), Arcobacter butzleri (74%) and Campylobacter spp (51%). The most common serovars of Salmonella obtained from humans with diarrhea were S. Risen, S. Stanley and S. Anatum. Most common serovars of Salmonella isolated from food were S. Anatum, S. Stanley, and S. Corvallis. Fifty-one percent and 25% of children infected with Salmonella and Campylobacter, respectively, infected with the same serotypes isolated from food samples, suggesting these pathogens are widespread in food and humans. Pulsed-field gel analysis of Salmonella spp revealed 65 pulsotypes, but no point-sources of salmonellosis were identified. Joint epidemiologic/laboratory studies are useful to describe the epidemiology of enteric pathogens in rural populations.

Design of an Agent-Based Model to Examine Population-Environment Interactions in Nang Rong District, Thailand.

The design of an Agent-Based Model (ABM) is described that integrates Social and Land Use Modules to examine population-environment interactions in a former agricultural frontier in Northeastern Thailand. The ABM is used to assess household income and wealth derived from agricultural production of lowland, rain-fed paddy rice and upland field crops in Nang Rong District as well as remittances returned to the household from family migrants who are engaged in off-farm employment in urban destinations. The ABM is supported by a longitudinal social survey of nearly 10,000 households, a deep satellite image time-series of land use change trajectories, multi-thematic social and ecological data organized within a GIS, and a suite of software modules that integrate data derived from an agricultural cropping system model (DSSAT - Decision Support for Agrotechnology Transfer) and a land suitability model (MAXENT - Maximum Entropy), in addition to multi-dimensional demographic survey data of individuals and households. The primary modules of the ABM are the Initialization Module, Migration Module, Assets Module, Land Suitability Module, Crop Yield Module, Fertilizer Module, and the Land Use Change Decision Module. The architecture of the ABM is described relative to module function and connectivity through uni-directional or bi-directional links. In general, the Social Modules simulate changes in human population and social networks, as well as changes in population migration and household assets, whereas the Land Use Modules simulate changes in land use types, land suitability, and crop yields. We emphasize the description of the Land Use Modules - the algorithms and interactions between the modules are described relative to the project goals of assessing household income and wealth relative to shifts in land use patterns, household demographics, population migration, social networks, and agricultural activities that collectively occur within a marginalized environment that is subjected to a suite of endogenous and exogenous dynamics.

Changes in Patient Characteristics and Practice Outcomes of a Tele-Urgent Care Clinic Pre- and Post-COVID-19 Telehealth Policy Expansions.

Introduction: The coronavirus 2019 pandemic (COVID-19) has resulted in major changes in lifestyle practices and healthcare delivery. The goal of this study was to examine changes in practice and service outcomes in a telehealth program before and after the federal and private telehealth policy expansion during the COVID-19 pandemic. These findings are particularly useful to understand what may be needed to overcome telehealth challenges in future disasters. Methods: We conducted a cross-sectional analysis of virtual visits through a statewide telehealth center embedded in a large academic healthcare system. Primary outcomes of this study were changes in telehealth visits pre- and post-policy expansions among at-risk populations. Results: A total of 2,132 telehealth visits were conducted: 1,530 (71.8 percent) patients were female, 1,561 (73.2 percent) were between the ages 18-50, 1,576 (74 percent) were uninsured, and 1,225 (57.5 percent) were from rural regions. The average number of telehealth visits per day increased from 14 to 33 visits post-expansion. A significant change in patient characteristics was found among senior, uninsured, and rural patients after the telehealth expansion.There was an 11 percent decrease in telehealth visits from very high vulnerability regions post-expansion compared to pre-expansion. There was a 15 percent decrease in visits resulting in prescription post-expansion (p-value<0.01). Conclusions: COVID-19 policy expansions expanded telehealth utilization among at-risk populations such as senior, uninsured, and rural patients while decompressing hospitals and emergency rooms and maintaining positive patient experiences. Further regulations are needed around virtual visits unintended consequences, software certification, and guidelines for workforce training.

Travel Time to Radiation Oncology Facilities in the United States and the Influence of Certificate of Need Policies.

PURPOSE: Radiation therapy often requires weeks of daily treatment making travel distance a known barrier to care. However, the full extent and variability of travel burden, defined by travel time, across the nation is poorly understood. Additionally, some states restrict radiation oncology (RO) services through Certificate of Need (CON) policies, but it is unknown how this affects travel times to care. Therefore, we aim to evaluate travel times to US RO facilities and assess the association with CON policies. METHODS AND MATERIALS: RO facilities were identified from the 2018 National Plan and Provider Enumeration System (n = 2302). Travel times from populated US census tracts to nearest facility were calculated; differences by rurality, area deprivation, and region were computed. Multivariable linear regression was used to estimate adjusted differences in travel time by area characteristics. Logistic regression was used to assess the association of state CON laws with travel time >1 hour. RESULTS: Among 72,471 census tracts, 92.4% were within 1 hour of the nearest radiation facility. Among the 12,453 rural tracts, 34.4% were >1 hour. On adjusted analysis, the 3054 isolated rural tracts had an estimated 58-minute (95% confidence interval [CI] 57, 59; P < .001) longer travel time than urban tracts. CON laws decreased rural travel time overall, but the association varied by region with decreased odds of prolonged travel in the South (P < .001), increased odds in the Northeast and Midwest (P < .001), and no association in the West (P = NS). CONCLUSIONS: Isolated rural US census tracts, accounting for 9.4 million Americans, have nearly 1-hour longer adjusted travel time to the nearest RO facility, compared with urban tracts. CON laws had region-dependent associations with prolonged travel.

National and subnational estimates of coverage and travel time to emergency obstetric care in Afghanistan: Modeling of spatial accessibility.

In Afghanistan, the risk of maternal death is among the highest in the world, with wide variation across the country. One explanation may be wide geographic disparities in access and use of maternal health care services. This study describes the spatial distribution of public facilities providing maternal health care in Afghanistan, specifically emergency obstetric care (EmOC), and the differences in travel time estimates using different transportation modes from 2010 to 2015 at the national and subnational levels. We conducted mapping and spatial analyses to measure the proportion of pregnant women able to access any EmOC health facility within 2 h by foot, animal, motor vehicle and a combination of transport modes. In 2015, adequate coverage of active public health facilities within 2 h of travel time was 36.6% by foot and 71.2% by a combination of transport modes. We found an 8.3% and 63.2% increase in access to EmOC facilities within 2 h of travel time by a combination of transport modes and by foot only, respectively, by 2015. Access to a combination of transportation options such as motor vehicles and animals may benefit pregnant women in reaching health facilities efficiently. Afghanistan made impressive gains in maternal healthcare access; despite these improvements, large disparities remain in geographic access by province and overall access to facilities is still poor.

Travel time to provider is associated with advanced stage at diagnosis among low income head and neck squamous cell carcinoma patients in North Carolina.

OBJECTIVE: There is considerable variation in the travel required for a patient with head and neck squamous cell carcinoma (HNSCC) to receive a diagnosis. The impact of this travel on the late diagnosis of cancer remains unexamined, even though presenting stage is the strongest predictor of mortality. Our aim is to determine whether travel time affects HNSCC stage at diagnosis independently of other risk factors, and whether this association is affected by socioeconomic status. MATERIALS AND METHODS: Cases were obtained from the CHANCE database, a population-based case-control study in North Carolina (n = 808). The mean age was 59.6 and 72% were male. Stage at diagnosis was categorized as early (T1-T2) or advanced (T3-T4) T stage and the presence or absence of nodal metastasis. Multivariate logistic regression models were used to estimate odds ratios for stage-at-diagnosis based on travel time, after adjustment for variables including demographics, income, insurance status, alcohol, and tobacco use. RESULTS: The adjusted odds ratio (OR) of advanced T-stage at diagnosis was 1.97 for each hour driven (95% CI 1.36-2.87). There was no association with nodal metastases. There was a significant interaction between travel time and income (p = 0.026) with a pattern of higher ORs for increased distance among lower income (<$20,000) patients compared to the ORs for higher income (>$20,000) patients. DISCUSSION: Travel time was an independent contributor to advanced T stage at diagnosis among low income patients. This suggests travel burden may be a barrier to early diagnosis of HNSCC for impoverished patients.

Geographic Distribution of Nonphysician Clinicians Who Independently Billed Medicare for Common Dermatologic Services in 2014.

Importance: Nurse practitioners (NPs) and physician assistants (PAs) are nonphysician clinicians (NPCs) who can deliver dermatology services. Many of these services are provided independently. Little is known about the types of services provided or where NPCs provide independent care. Objective: To examine characteristics of dermatology care for Medicare enrollees billed independently by NPCs. Design, Setting, and Participants: Retrospective review of the 2014 Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File, which reflects fee-for-service payments to clinicians for services rendered to Medicare beneficiaries. Clinician location was matched with county-level demographic data from the American Community Survey, US Census Bureau. Clinicians identified using National Provider Identifier as NPs or PAs with at least 11 claims for common dermatology-associated Healthcare Common Procedure Coding System procedure codes were included. Main Outcomes and Measures: Total services provided by service type category, density of dermatologists and nondermatologists who perform dermatology-related services, and geographic location by county. Results: Among the cohort of NPCs were 824 NPs (770 [93.5%] female) and 2083 PAs (1602 [76.9%] female) who independently billed Medicare $59 438 802 and $171 645 943, respectively. Dermatologists were affiliated with 2667 (92%) independently billing NPCs. Most payments were for non-evaluation and management services including destruction of premalignant lesions, biopsies, excisions of skin cancer, surgical repairs, flaps/grafts, and interpretation of pathologic analysis. Nurse practitioners and PAs billed for a similar distribution of service categories overall. A total of 2062 (70.9%) NPCs practiced in counties with dermatologist density of greater than 4 per 100 000 population. Only 3.0% (86) of independently billing NPCs practiced in counties without a dermatologist. Both dermatologists and NPCs were less likely to be in rural counties than in urban counties. Conclusions and Relevance: Nonphysician clinicians independently billed for a wide variety of complex dermatologic procedures. Most independently billing NPCs practice in counties with higher dermatologist densities, and nearly all these NPCs were affiliated with dermatologists. Further study of NPC training and integration with the dermatology discipline is an important part of addressing the changing US dermatology workforce.

Intestinal parasitic infections among pre-school children in Sangkhlaburi, Thailand.

This study was conducted to investigate the presence of intestinal parasites among pre-school children (aged 3 months to 5 years) in Sangkhlaburi, a rural district in the west of Thailand along the Thai-Myanmar border. Stool specimens were collected from October 2001 through October 2002. A total of 472 pre-school children, 233 males and 239 females, 236 children with diarrhea and 236 asymptomatic children were recruited for the study. Each specimen was processed and examined by direct wet smear, modified acid fast stain, formalin-ethylacetate sedimentation concentration technique, and trichrome stain. In detecting Giardia lamblia and Cryptosporidium species ProSpecT Microplate assays (Alexon-Trend, Lenexa, KS) were performed. There were 107 individuals (22.7%), 41 diarrheal and 66 asymptomatic children, infected with intestinal parasites. The most frequent parasites identified in cases and controls were G. lamblia and Cryptosporidium spp. Eighteen specimens (3.8%) showed mixed parasite infections. Highest proportion of intestinal parasites occurred during the rainy season (June-October).

Geographic Information Systems Mapping of Diabetic Retinopathy in an Ocular Telemedicine Network.

Importance: Minimal information exists on the use of geographic information systems mapping for visualizing access barriers to eye care for patients with diabetes. Objective: To use geographic information systems mapping techniques to visualize (1) the locations of patients participating in the North Carolina Diabetic Retinopathy Telemedicine Network, (2) the locations of primary care clinicians and ophthalmologists across the state, and (3) the travel times associated with traveling to the 5 primary care clinics in our study. Design, Setting, and Participants: Cross-sectional study conducted from January 6, 2014, to November 1, 2015, at 5 Area Health Education Center primary care clinics that serve rural and underserved populations in North Carolina. In total, 1787 patients with diabetes received retinal screening photographs with remote expert interpretation to determine the presence and severity of diabetic retinopathy. Participants included patients 18 years or older with type 1 or type 2 diabetes who presented to these 5 clinics for their routine diabetes care. Main Outcomes and Measures: Development of qualitative maps illustrating the density of patients with diabetes and their distribution around the 5 North Carolina Diabetic Retinopathy Telemedicine Network sites by zip code and the density of ophthalmologists and primary care clinicians by zip code relative to US Census Urban Areas. A travel time map was also created using road network analysis to determine all areas that can be reached by car in a user-specified amount of time. Results: Mean (SD) age of patients was 55.4 (12.7) years. Women made up 62.7% of the study population. The study included more African American patients (55.4%) compared with white (35.5%) and Hispanic (5.8%) patients. The mean (SD) hemoglobin A1c level was 7.8% (2.4%) (to convert to proportion of total hemoglobin, multiply by 0.01), and the mean (SD) duration of diabetes was 9.2 (8.2) years. Whereas the clinics located in Greensboro, Asheville, and Fayetteville screened patients from more immediate surrounding areas, the Greenville site had the widest distribution of zip codes, suggesting that patients travel from greater distances to reach this facility. Primary care clinicians were spread somewhat uniformly across the state, whereas ophthalmologists were concentrated around urban centers. Also, the number and type of surface roads surrounding the clinics determined the distance and time patients must travel to receive care. Conclusions and Relevance: Geographic information systems mapping is a useful technique for visualizing geographic access barriers to eye care for patients with diabetes and may help to identify underserved areas that would benefit from the expansion of retinal screening programs via telemedicine.

Effective treatment of uncomplicated Plasmodium falciparum malaria with azithromycin-quinine combinations: a randomized, dose-ranging study.

Azithromycin, the most potent antimalarial macrolide antibiotic, is synergistic with quinine against Plasmodium falciparum in vitro. We assessed combinations of azithromycin and quinine against uncomplicated P. falciparum malaria at the Armed Forces Research Institute of Medical Sciences-Kwai River Clinical Center along the Thailand-Myanmar border, an area with a high prevalence of multidrug-resistant P. falciparum. Four regimens were assessed in an open-label dose-ranging design involving 61 volunteers. All received oral quinine (Q; 30 mg/kg/day divided every 8 hours for 3 days) with oral azithromycin (Az; 500 mg twice a day for 3 days, 500 mg twice a day for 5 days, or 500 mg three times a day for 3 days). A comparator group received quinine and doxycycline (Dx; 100 mg twice a day for 7 days). Study observation was 28 days per protocol. Sixty volunteers completed the study. Seven days of QDx cured 100% of the volunteers. One failure occurred in the lowest QAz regimen (on day 28) and none occurred in either of the two higher Az regimens. Cinchonism occurred in nearly all subjects. Overall, the azithromycin regimens were well tolerated, and no volunteers discontinued therapy. Three- and five-day azithromycin-quinine combination therapy appears safe, well tolerated, and effective in curing drug-resistant P. falciparum malaria. Further evaluation, especially in pediatric and obstetric populations, is warranted.

Causes of fever in adults on the Thai-Myanmar border.

A hospital-based study was conducted along the Thai-Myanmar border to provide greater knowledge of the causes of febrile illness and to determine what zoonotic and vector-borne emerging infectious diseases might be present. A total of 613 adults were enrolled from June 1999 to March 2002. Cases were classified based on clinical findings and laboratory results. An etiologic diagnosis was made for 48% of subjects. Malaria was the most common diagnosis, accounting for 25% of subjects, with two-thirds Plasmodium falciparum. Serologic evidence for leptospirosis was found in 17% of subjects. Other etiologic diagnoses included rickettsial infections, dengue fever, and typhoid. The most frequent clinical diagnoses were nonspecific febrile illness, respiratory infections, and gastroenteritis. Clinical associations were generally not predictive of etiologic diagnosis. Apparent dual diagnoses were common, particularly for malaria and leptospirosis. Findings have been used to modify treatment of unspecified febrile illness in the area.

pfmdr1 genotyping and in vivo mefloquine resistance on the Thai-Myanmar border.

Molecular markers have been proposed as a method of monitoring malaria drug resistance and could potentially be used to prolong the life span of antimalarial drugs. Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum gene pfmdr1 and increased gene copy number have been associated with in vitro drug resistance but have not been well studied in vivo. In a prospective cohort study of malaria patients receiving mefloquine treatment on the Thai-Myanmar border, there was no significant association between either pfmdr1 SNPs or in vitro drug sensitivity and mefloquine resistance in vivo. Increased pfmdr1 gene copy number was significantly associated with recrudescence (relative risk 2.30, 95% CI 1.27-4.15). pfmdr1 gene copy number may be a useful surveillance tool for mefloquine-resistant falciparum malaria in Thailand.

Randomized, controlled, double-blind trial of daily oral azithromycin in adults for the prophylaxis of Plasmodium vivax malaria in Western Thailand.

We assessed the prophylactic efficacy of azithromycin (250 mg/day) against malaria in 276 adults in western Thailand in a randomized, double-blind, placebo-controlled trial. After antimalarial suppressive treatment, volunteers were randomized in a 2:1 ratio to either the azithromycin or placebo, respectively. Study medication was given for an average of 74 days. The azithromycin group (n = 179) had five endpoint parasitemias (1 Plasmodium vivax and 4 P. falciparum), and the placebo group (n = 97) had 28 endpoint parasitemias (21 P. vivax, 5 P. falciparum, and 2 mixed infections). Adverse events and compliance and withdrawal rates were similar in both groups. The protective efficacy (PE) of azithromycin was 98% for P. vivax (95% confidence interval [CI] = 88-100%). There were too few cases to reliably estimate the efficacy of azithromycin for P. falciparum (PE =71%, 95% C =-14-94%). We conclude that daily azithromycin was safe, well-tolerated, and had a high efficacy for the prevention of P. vivax malaria.